Valve seat tool



De.22,1936. F, Q ALBERTQDN l 2,065,486v

VALVE SEAT TOOL Original Filed July 1'7, 1931 3 Sheets-Sheet 1 246 12g233 2]'9 l n 103 Dec. 22, 1936. l F. 0, ALBERTSON 2,065,486

VALVE SEAT TOOL Original Filed July l'7, 1931 y ml W 5 Sheets-Sheet 2 Il di @.5 i 122 @l 52]] ,ff-[ ,205357198 JM zozo TTI j 151 203 .9 1.95 1|V205 1.96. i 1.93 @j X391 Q 20560 Jn 1 7a- 7g 5% t jzz y i Dec. 22,1936. F Q` LBERTSQN 2,065,486

VALVE SEAT TOOL Original Filed July 17, 1931 5 Sheets-Sheet 3 j? 22,62ze UNITED STATES PATENT OFFICE VALVE SEA'l` TOOL Frans 0. Albertson,Sioux City, Iowa, assignor to Albertson & Company, Inc., Sioux City,Iowa, a

corporation of Iowa Application YJuly 17, 1931, Serial No. 551,310Renewed November 16, 1936 i 10 Claims.

The present invention relates to valve seat tools and is particularlyconcerned with valve seat tools adapted to be used in refinishing orreconstructing the valve seats of internal combustion engines.

Thepresent tools are peculiarly adapted to be used. in cutting anannular recess in the valve seat oan internal combustion engine, forreceiving anew valve seat ring, for repairing the valve seat orfurnishing it with a ring seat having more desirable characteristicsthan the metal of which the motor block is constructed.

One of the objects of the present invention is the provision of animproved valve seat tool assembly, by means of which valve seats andring recesses may be cut more accurately than with the devices of theprior art.

Another object is the provision of an improved power actuated valve seattool, by means of which valve seats or ring recesses may be cut morequickly and uniformly, thereby saving time and labor.

Another object is the provision of an improved power drive unit, bymeans of which the applicants standard drill motor may be utilized fordriving the cutter of a ring tool set.

Another object is the provision of an improved automatic feed, by meansof which the cutter is automatically fed downward at a predeterminedrate of cut, thereby preventing any overworking of the cutter, orbinding of the tool in its bearings, and eliminating the necessity formanual manipulation of the cutter feed.

Another object is the provision of an automatic feed screw of the typedescribed, which may be utilized in the valve seat tool sets covered bymy prior applications.

Another object is the provision of an improved power actuated valve seattool assembly, which 40 is adapted to cut valve seats or ring recessesin accurately concentrical position with respect to the axis of a valveguide.

Another object is the provision of an improved valve seat tool set,which is sturdy, capable of 45 being economically manufactured, andcapable of long and efiicient service with a minimum amount of repair orreplacement.

Other objects and advantages of the invention will be apparent from thefollowing description, and from the accompanying drawings, in whichsimilar characters of reference indicate similar parts throughout theseveral views.

Referring to the drawings, of which there are three sheets;

Fig. 1 is a view in perspective of the complete valve seat tool assemblyin the process of cutting a recess for a valve seat ring;

Fig. 2 is a plan view of the clamp and floating Astud for preventingrotation of the power drive gear casing without binding the drive shaft,taken on the plane of the line 2--2 of Fig. l;

Y Fig. 3 is an elevational view ofthe tool fixture in partial section,on a vertical plane with the tool holder, cutter, and pilot inelevation;

Fig. 4 is a plan View of the valve seat xture with the tool holder orshaft in section, taken on the plane of the line 4-4 of Fig. 3; Y

' Fig. 5 is a fragmentary, sectional view of one of the clamping bolts,taken on the plane of the line 5--5 of Fig. 4;

Fig. 6 is a vertical, sectional View taken through the axis of theshafts of the power drive` shown in Fig. 1. Y

The complete power actuated valve seat tool assembly shown in Fig. 1,preferably comprises the motor indicated in its entirety by the numeralI0, the power drive unit II, and the valve seat tool fixture I2.

The power unit or motor I0 preferably comprises the applicants motordrill unit, which consists of an electric motor I3 having a pair ofoppositely located transverse handles lli and I5, the casing I3containing a series motor of the commutator type, which is connected byappropriate gear reduction mechanism in the gear casing I6, with theshaft of a chuck I'I.

The motor casing I3 includes a switch casing I8 containing a latch-tripor snap switch adaptedto be actuated by the trigger I9 adjacent thehandle I4, and the gear reduction casing I6 preferably includesreduction gears for reducing the speed from that of the motor shaft tothe appropriate speed for a drill at the chuckV I'I. For example, thesegears may consist of a motor shaft pinion, an enlarged gear meshing saidpinion, a second pinion driven by said enlarged gear, and a secondenlarged gear carried by the shaft of chuck I'l. The motor I0 may alsobe provided with a so-called spade handle iixture 20 1ocated on theupper end of the motor for more convenient manipulation under certainconditions.

The speed at which a drill chuck should be driven would be too fast forthe operation of a valve seat cutting tool and in order to `utilize thesame motor as a power drive for drilling and for valve seat work, thetool assembly is preferably provided with a power drive unit II, thedetails of which are shown in section in Fig. 6.

The power drive unit II comprises a casing head 49 and the end of thebore 4|.

which may consist of upper and lower castings 22, 2| for enclosing thegears and shafts and providing appropriate bearings for these machineelements. The lower power drive casting 2| is preferably provided with alaterally projecting portion 23 which has a threaded bore 24 forreceiving a stud bolt or rod 25. A lock nut 26 on the bolt 25 assuresthe fixety of this bolt in the casting 2|, and the bolt projects upwardfor engagement in a slot 21 formed in a clamping xture indicated in itsentirety by the numeral 28.

The clamping xture 28 consists of a pair of clamping members 29 and 39formed with oppositely located jaws 3| and 32, and these clampingmembers may be constructed of cast metal. The jaws 3| and 32 have innercylindrical surfaces 33, 34, which may be substantially complementary tothe outer cylindrical surface 35 of the motor gear casing |6 above thechuck |1. The clamping members 29 and 39 are pivoted together by a boltor pin 36 passing through the registering bores 31 in the clampingmembers 29 and 30, and axial movement of the clamping members 29 and 39on the bolt 36 is limited by the head of the bolt at one end and acotter pin at the other end of the bolt.

The clamping member 29 is preferably bifurcated as at 39 adjacent thebolt 31, for receiving the portion 49 of the clamping member 39 betweenthe bifurcated portions 39.

The clamping members 29 and 39 are provided with aligned bores 4|, 42for receiving the clamping bolt 43, and a helical compression spring 44between the clamping members on the bolt 43 urges the clamping membersapart and facilitates their release from the motor. The bolt 43 ispreferably substantially smaller than the bores 4|, 42, to permit thepivotal movement of the clamping members 29 and 39 on the bolt 31, andthe bolt 43 may be provided with a frustoconical portion 45 adjacent thehead for engaging the enlarged bore 4| and centering the bolt. Thefrusto-conical portion 45 permits a limited pivotal engagement betweenthe lower side of the The clamping member 29 is also preferably providedwith a transverse groove 41 adjacent bore 4| for receiving the head 46of bolt 43, and preventing rotation of the head 46. The spring 44constantly urges the clamping member 29 into engagement with head 46 andmaintains the lower portion of head 46 in the groove 41.

At its opposite end, the bolt 43 carries a collar 48 having afrusto-conical surface 49 for engaging in the enlarged bore 42 andpermitting a limited pivotal movement between the bolt and clampingmember at said frusto-conical surface. The collar 48 is provided with anenlarged bore 59 so that the collar 48 may automatically adjust itselfin its engagement with the frustoconical recess 5|. The bolt 43 is alsoprovided with a nut 52 for engaging collar 48 and the nut 52 constitutesa force multiplying device for forcing the clamping members 29 and 30intol engagement with the cylindrical portion 35 of the motor casing.

The slot 21 in clamping member 39 comprises a slot of sufficient widthto slidably receive the bolt 25, and the slot 21 extends in a radialdirection with respect to the center of the clamping surfaces 33, 34, orthe axis of chuck |1.

Referring to Fig. 6 the lower casting 2| of the power unit casing isprovided with a gear chamber 53 for receiving the spur gears 54, 55,pinions 56, 51 and shafts 58 59 and 69. The casing member 2| may beformed with a cylindrical bore or bearing 6| for receiving the driveshaft 69 and with an inwardly protruding portion of the bearing 62having a substantially flat end surface 63 for a thrust bearing. Theshaft 69 is preferably provided with a reduced end 94 forming an annularshoulder and the reduced end 64 carries the spur gear 54 to which it iskeyed by means of a key 65 driven into a slot formed partially in shaftend 64 and partially in the bore of gear 54.

The gear 54 may be provided with a bore 66 and a counter-bore 61, theend 64 of shaft 69 extending merely into the bore 66. The counterbore 61is provided with an outer race 68 which may be a pressed frictional t inthe counterbore 61 and the reduced end 69 of shaft 59 carries the secondrace 19. The race 19 also has a pressed frictional t on the reduced end69 and the races 68 and 10 are provided with circular grooves 1|, 12arranged to serve both as a thrust bearing and an ordinary ball-bearing.That is, the race 69 has a portion 13 which projects under the balls 14while the race 19 has a portion 15 which projects over the balls 14. Thepinion 51 may consist of an integral part of shaft 59, the shaft 59being rotatably mounted in a bearing sleeve 16 carried by the casting22. The upper end 11 of shaft 59 is adapted to be gripped by the chuckI1 of the drill motor |9 to transmit power from the motor to the powerdrive unit The casting 22 constitutes a cover for the casing of thepower drive unit and is secured to the lower casting 2| by the screwbolts 18 which pass through cover 22 and are threaded into bores 19 incasing member 2|. The shaft 53 is rotatably mounted in a bearing 89formed in cover 22 and in a second bearing 8| formed in casing member2|. The pinion 56 is adapted to mesh with spur gear 54 and may form anintegral part of shaft 58, while spur gear 55 is adapted to mesh withpinion 51 and is fixedly secured to shaft 58 by a key or spline 82.

The shaft 69 is provided with forked ends 83, 84, which are adapted toreceive between them a pivot block 85, the block 85 being pivotallysecured to the ends 83, 84 by a riveted pin 86. The block 85 is providedwith reduced cylindrical ends 81 which are pivotally mounted in thebores 88 located in the forked ends 89 of a tting 90. The reduced ends81 may consist of pins driven into the bores in the ends of blocks 85and it will be noted that the pivot 86 is transversely arranged withrespect to the pivot 81. The fitting 99 is provided with a non-circularsocket 9| adapted to receive the squared end 92 of a tool holder 93.

It will thus be observed that the power drive unit is provided with auniversal joint connection between the shaft 69 and the tool holder 93,thereby eliminating the necessity for holding the motor in axialalignment with the tool holder shaft 93. Furthermore, the drive shaft 11of the power drive unit is supported in the chuck |1 and rotation of thecasing is prevented by the bolt 25 which floats in the radiallyextending groove 21. The bolt 25 is, however, permitted to shift inwardor outward of the groove 21 in a radial direction, as the shaft 59rotates, thereby preventing any binding of the shafts in their bearings,on account of some slight misalignment between the axes of the twocasings I3 and 2|. The present arrangement permits the use of anordinary drill motor for driving valve seat tools as the speed reductionacbomplished by the 'power drive 'unit II brings the speed of the shaft60 down to that required for actuating valve tools.

Referring` to Figs. l, 3 and4, the valve seat tool nxture |2 preferablyincludes a supporting body 94, a universally adjustable support 95, anautomatic feed screw unit 96, tool holder 93, cutter 91 and pilot 98.While the tool is illustrated in connection with the ring recess cutter91 of the type disclosed in my prior application, Serial No. 536,520,filed May 11, 1931, it should be understood that the present assemblymay also be used with valve seat reamers or finishing tools` of allkinds.

The cutter 91 isprovided with a tapered bore 9 and has a blade xedlysecured in an axially extending slot. The blade |00 is provided with aradially extending cutting edge |0| and an axially extending cuttingedge |02 for cutting an'annular recess |03 of substantially rectangularcross-section to receive a new valve seat ring as described in my priorapplications.

The tool holder 93 comprises a shaft having an elongated cylindrical.surface |04 terminating in one end in the non-circular portion 92 andat the other end'in the tapered portion |05. The cutter 91 is adapted tobe wedged on the tapered portion to secure the cutter on the toolholder.

The pilot 98 is Vpreferably of the type described in my priorapplication, Serial No. 538,504, led May 19, 1931, on tapered pilotstems. These tapered pilots are provided with a cylindrical portion |06adapted to fit the cylindrical valve guide |01 within a tolerance ofone-thousandth of an inch, or less, and this t is accomplished byproviding sets of pilots which increase in size by extremely smallincrements.

The cylindrical portion |06 extends through the major portion of thevalve stem guide |01 and is adapted to engage that portion of the valvestem guide intermediate the ends where the guide is still accuratelycylindrical. The valve stem guide |01 carried `by motor block |08 isgenerally likely to be rounded out at the vpoint |09 -adjacent eitherend, and therefore the ends of the guide are not adapted to effectaccurate, axial location of the pilot, but may be used for securing thepilot fixedly in the block in the present construction.

The pilots 98 are therefore provided with a frusto-conical portion ||0adapted to come into wedging engagement with the upper inner surface ofthe valve stern guide |01, and this taper is so gradual that the pilotmay be xedly secured in the guide ,by merely forcing it down androtating it. The taper, for example, should preferably be abouttwenty-two-thousandths of an inch per foot, or between the limits offifteen to thirty-thousandths of an inch taper per foot of length. Thatis, in the example given, the diameter of the pilot decreases twenty-twothousandths of an inch for each foot of its length.

It should be clearly understood that the centering and location of thepilot stem is accomplished by the cylindrical portion |06, but the pilotstem is secured in position by the gradually tapered wedging portionIIO. The pilot 98 is also provided with an upper cylindrical portion I||terminating in a non-circular end ||2 for `engagement with wrenches lortools, if desired, and the pilot may be provided with an aperture I I3for receiving a pin to be grasped by. the hand -iri forcing the pilothome in the guide |01.

4"The tool holder 93 is provided with .a complementary cylindrical bore|I4 for slidably and rotatably receiving the cylindrical portion I I ofpilot 08, and the cutter 91 is thus supported in accurate axialalignment with the axis of the valve stem guide |01.

The body 94 of the valve seat fixture may comprise a c ast metal memberwhich is provided with an elongated curved slot I5 extending verticallythrough the body 94 for receiving a stud bolt ||6 carried by the motorblock |08. The curved slot ||5 enables the body 94 to be secured in amultiplicity of different positions on the engine block |08 so thatprovision is made for locating the fixture pro-perly on every moderntype of motor block without interference with adjacent studs. The stud||6 is one of the studs ordinarily used for securing the cylinder headin place, and is used with a Washer ||1 and nut IIB to clamp the body 94in place.

The body 94 is provided with a. laterally projecting lug ||9 having avertically extending flat surface |20. A bore |2| extends through thelug I |9 and communicates with a counterbore |22.

The bore I2| is adapted to receive the cylindrical trunnion |23 on amovable supporting body |24, and the movable supporting body |24 isprovided with a thrust bearing or annular shoulder The trunnion |23 isprovided with a threaded bore I 26 for receiving screw bolt |21 andwasher |28 is secured on the end of trunnion |23 by the head of bolt|21. A helical compression spring |29 is compressed between Washer |28and the aiznular shoulder |30 at the end of counter-bore faces |20 and I25 into frictional engagement with each other and holds the trunnion inany predetermined rotative position during its ,adjustment.

The lug I9 is preferably split or provided with a slot |30 at one side,communicating with the bore |2I throughout its length, and a clampingbolt |3| passes through a bore in the upper half |32 of lug I I9, and isthreaded into the lower half |33 of lug II9. The bolt I3I is adapted toforce the portions |32 and |33 toward each other, clamping the trunnion|23 and xedly securing the movable body |24 in adjusted position.

The movable body |24 is provided with two portions |34 and |35 atsubstantially right angles to each other, and the part |35 is providedwith a bore |36 having a threaded stud bolt |31 xedly secured Vin saidbore. The stud bolt |31 is provided vwith an enlarged cylindricalsurface |38, forming a trunnion for the feed screw supporting fixture|39. The body |24 is provided With a bore |40 for receiving the trunnion|38 and with a counter-bore |4I having an annular shoulder |42 forreceiving a spring washer |43.

The spring washer |43 may consist of an annular sheet metal member ofresilient steel, which is curved laterally at |44 so that it is exedwhen the washer |45 is forced into counter-bore |4| by nut |46 on theopposite threaded end |41 of stud bolt |31. Ihe feed screw supportingfixture |39 is thus rotatably mounted on the movable supporting body |24and provided with friction means for preventing its free rotation andretaining it in any adjusted position. The fixture |39 may, however, beclamped in any adjusted position by threading the nut |46 home on thebolt |31, thereby holding the feed screw |48 in a predeterminedposition.

The feed screw supporting fixture |39 comprises ,an annular metal memberwhich is provided with The spring |29 constantly urges the sura threadedbore |49 for receiving the feed screw |48. The supporting fixture |39 isprovided on its upper surface with one or more gauge pins |50 comprisinghardened steel pins having fiattened ends |5| for engaging the iiatlower surface |52 on the body of the feed screw |48. The pins |50 arexedly mounted in the fixture |39 by driving them into bores |53 and theyare adapted to stop the automatic feed of the feed screw when thecutting operation has proceeded to a predetermined depth.

In order to predetermine the depth of cut, the distance between the flatend |5| and fiat annular surface |52 is rst predetermined by rotatingthe feed screw |48 in its supporting fixture |39 until this distance isa predetermined amount, such as, for instance, the depth of a new Valveseat ring to be inserted in the recess which is being cut.

It will thus be observed that the feed screw |48 may be adjusted uponthe axis of the bolt |31 by adjusting the position of the fixture |39,and it may also be adjusted upon the axis of the trunnion |23 byadjusting the body |24. Both of these adjustable bodies may be iixedlysecured in place so that the tool may be adjusted and secured for valveseats extending in any direction with respect to the surfaceof the motorblock.

It should be noted, however, that in the present devices the position ofthe cutter 91 is predetermined by the pilot 98, which is accuratelyaligned with the valve stem guide |01, and the automatic feed screw unit96 is so constructed as to permit a limited universal movement betweenthe bearing for the tool holder 93 and the supporting fixture 94, sothat the cutter may adjust itself to the position determined by thepilot stem.

The automatic feed screw unit 96 preferably comprises the feed screw|48, a guide |54 for the tool holder 93, and friction means |55 forconnecting these members and permitting a predetermined amount ofslippage, whereby the feed screw |48 is driven at a slower rate ofrotation than the tool holder 93.

The feed screw |48 may comprise a tubular metal body having an enlargedbore |56 for providing a clearance about the tool holder 93. The bore|56 is provided with an annular shoulder |51 forming a seat for ahelical compression spring |58, the other end of which engages the end|59 of guide |54. Spring |58 is adapted to counteract the pressureexerted by springs |60 acting on the opposite side of the self-aligninganti-friction bearings indicated in their entirety by the numeral |6I,and thereby adapted to maintain the balls |62 of bearings |6| inconstant engagement with the races |63, |64, so as to take up anyback-lash in the movement of the tool holder 93 and guide |54. In otherwords, there is no back-lash or looseness to be taken up by the bearingswhen the cutter 91 rst comes into engagement with the motor block |98 byvirtue of the fact that the spring |58 always holds the parts in activeengagement, and the depth of the cut may thus be accuratelypredetermined by having the cutter located in engagement with thesurface of the motor block |08 when the feed screw is adjusted.

The feed screw |48 has an outer threaded surface |65 for engaging thethreads in bore |49 and above the feed screw supporting fixture 95, thebody of the feed screw is enlarged in diameter at |66. 'I'he enlargedpart |66 of the feed screw is provided vwith an enlarged bore |61 havingan annular shoulder |68 which forms a seat for the outer race |63.

The race |63 comprises a, hardened steel annular member having an outercylindrical surface adapted to be frictionally engaged in the bore |61and having an annular groove |69 of circular cross-section formed insidethe race I 63. The radius of curvature of the cross-sectional curve ofthis groove |69 is located at the axis of the tool holder 93 andsubstantially midway between the upper and lower surfaces |10, |1| ofthe race |63. The assembly, including the tool holder 93, guide |54,race |64 and balls |62, is thus adapted to rotate about a multiplicityof axes passing through the point |12, and the tool holder 93automatically aligns itself with the position of the pilot 98.

The race |63 is engaged at its upper end |1| by the outer clutch ring|13 which comprises a hardened steel member having a substantiallycylindrical outer surface adapted to be received in the bore |61, andhaving an inner frustoconical surface |14. The race |63 and outer clutchring |13 are retained in the casing |66 by spinning over the upper endof casing |66 at |15.

The guide |54 comprises a tubular metal member preferably constructed oftool steel and formed with a bore |16 adapted to slidably engage thetool holder 93. The lower end of the guide |64 is engaged by spring |58and is provided with an annular shoulder |11 adapted to support theinner race |64, which engages the outer cylindrical surface |18 of theguide |54.

Above the cylindrical surface |18, the guide |54 is provided with athreaded surface |19 serving to secure in place the inner clutch ring|80, and also serving as a threaded support for the adjustably mountedpressure ring or thrust bearing |8|. The threads |65 of the feed screwE48 are preferably right-hand threads, in order to take advantage of thefact that the drive is taken from that end of the motor, rotating in aright-hand direction, and the same motor which drives the cutter 91 isalso employed for driving the automatic feed screw unit 96. The threadson the surface |19 are preferably made lefthand threads in order thatthe rotation of the tool holder 93 with the thrust bearing or pressureplate |8| may not tend to loosen the pressure on springs |60. That is,there is no tendency for the inertia of the parts in the operation ofthe device, to cause the adjustable pressure devices to diminish thepressure on the friction feed.

The inner race |64 is preferably provided with one or more annulargrooves |82, |83 extending about the periphery of the race |64, and thegrooves |82, |83 are also circular in cross-section, the curvaturecorresponding substantially to the curvature of the balls |62.

The balls |62 are also preferably provided with a retaining device |84adapted to hold the balls in predetermined spaced position to preventtheir coming out of the races |63, |64, and to eliminate the necessityfor such a large number of balls as would otherwise be necessary. Thegrooves |82, |83 provide recesses in which the balls |62 nest, and fromwhich they cannot move in an axial direction, and the anti-frictionbearing |6| is thus a self-aligning anti-friction thrust bearing adaptedto withstand the thrust which is exerted against the fixture 94 by thereaction from the cutter 91.

The inner race |64 is secured on guide |54 by the inner 'clutch ring |80which comprises an 75 annular steel member having an inner threadedsurface |85 with left-hand threads for engaging the threads on guide|513. The inner clutch ring is also provided with an outerfrusto-conical surface |80, the largest part'of which is adapted to bereceived inside the smallest diameter of the frusto-conical surface |14on the outer clutch ring |13. Between the clutch rings |13, |80, thefrusto-conical surfaces |14, form an annular groove of substantiallyV-shaped cross-section.

The friction means |86 forcausing the feed screw |48 to be driven withtool holder 93 and guide |54, may consist of an annular leather ringcomprising a strip of tough leather of substantially triangularcross-section, having its ends joined together by a wire clip. The outerside |01 of the leather ring |55 forms a frusto-conical surface forengagement with the complementary frusto-conical surface |14 on theouter thrust ring |13. The inner side |88 of the leather ring |55 formsan inner frustoconical surface for frictional engagement with thefrusto-conical surface |86 of inner clutch ring |80. The upper surface|89 of the leather ring may be engaged by a pressure ring |90 fordriving the leather ring |55 into the groove between the clutch rings|13, |80 and determining the amount of pressure exerted on the clutch,and therefore the amount of slippage between the feed screw and the toolholder.

It should be understood that while a leather clutch facing ring isdescribed, various forms of clutch facing materials may be employed, andvarious shapes of clutch surfaces may be utilized, but the presentspecific arrangement has been found to give very good results for a longperiod of time, with a minimum amount of adjustment and replacement.

The pressure ring |90 comprises an annular steel member having a lowerflat surface for slidably engaging the leather ring |55 and having abore |9| for slidably mounting the pressure ring |90 on the cylindricalportion |92 of the inner clutch ring |80. Upon its upper surface, thepressure ring |90 carries a resilient spring plate |93 which is similarin shape, and which is secured to the pressure plate by a plurality ofrivets passing through both of these parts, and the spring plate |93 isprovided with a multiplie` ity of symmetrically located spring tongues|00 which are punched out of the body of the spring plate |93 and bentupward to engage the lower side |94 of a thrust bearing race |95.

'Ihe thrust bearing race |95 comprises an annular metal plate formed ofhardened steel and having a bore |96v for slidably receiving thethreaded guide |54 with a slight clearance. Above the race are locatedthe ballbearing holder |91 and the ballbearings |98. The ballbearingholder |91 may consist of an annular metal member of bearing metalformed with a plurality of staggered spherical recesses |99V forreceiving the balls |98.

The recesses |99 may comprise bores having a smaller opening 200 at oneside for preventing the balls |98 from passing through, and having themetal adjacent the opening 20| at the other side, spun over to decreasethe size of the opening of the bore at that side and retain the ball inthe recess |99. The balls i90 project beyond the at surfaces of theretaining ring |91 at the top and bottom, and are adapted to engage thelower race |95 on one side and the flat surface 202 of the pressureadiusztment'ring |8| on the other side, the latter surface alsoperforming the function of an upper race.

The pressure adjustment ring |8| comprises an annular metal memberpreferably constructed of tool steel and provided with a centrally1ocated bore 203 having left-hand threads for engaging the threads onguide |54. The outer cylindrical surface 204 of thepressure adjustmentmember carries a tubular skirt or casing member 205, the outer surface200 of which is preferably knurled as shown in Fig. 1, for convenientgrasp with the hand in adjusting the'spring pressure on the frictiondevice.

The tubular casing 205 may be provided with an enlarged bore 205 forreceiving the annular member |8| and `the upper end of the tubularmember 205 may be spun over at 201 to clamp the annular member |8|between the shoulder 298 and the sp-un end 201. Tubular member 205should preferably be long enough to extend down to the casing |55 andthe bore 209 should be large enough to receive the casing |56 as thepressure member is threaded downward on the guide |54.

The guide |54 is provided with an upper end portion 2|0 of reduceddiameter forming an annular shoulder 2||, and the upper end 2|0 ispreferably provided with a multiplicity of slots 2 l2 uniformly spacedabout the periphery of the end 2li) and extending axially into the end.A e

clamping member 2|3 fits about the reduced end 2|0, and is preferablyprovided with a pin 2| 4 extending through a bore in the clamping memberZIB and end 2|0 to prevent relative rotation between the clamping memberand the guide |54.

The clamping member 2|3 is provided with a pair of late-rally projectinglugs 2|5, 2|5, the former of which is provided with a threaded bore 2 1,and the latter with an ordinary circular bore 2l8. A clamping bolt 2|9extends through the bore 2|8 and is threaded into the bore 2|1 and thehead of bolt 2|9 draws the lugs 2|5 and ZIB together to reduce the sizeof the bore 220 in clamping member 2|3. The relationship of the partsshould be such that when the bolt 2|9 is threaded home, the member 2|3clamps 'the split portions 22| of the end 2|0 together on the toolholder 93 and fixedly secures the tool holder 93 to the guide |54.

The method of manipulation, and the operation of the present apparatusis as follows. A pilot stem 93 is selected which will most closely t inthe Valve stem guide |01, and this fit can be accomplished by selectingthe appropriate pilot stem from the set of pilots describedin my priorapplication, in which the sizes vary by eX- tremely small incrementsfrom the standard measurements for guides. By means of these cylindricalpilot stems adapted to fit in the guides, the pilot may be selectedwhich will be accurately centered in the guide by that portion of theguide which is intermediate its ends, and which is still substantiallycylindrical in form, as distinguished from the ends of the valve stemguide which are apt to be rounded out.

The pilots described are provided with a tapered portion of Vsuchgradual taper that the pilot is adapted to be wedged into the guide atthe upper end and xedly secured in the guide solely by the wedgingaction of the frusto-conical or gradually tapered portion of the pilot.

The clamping bolt |3| is first loosened and the clamping nut |46 isloosened so that the body oi' the tool may move freely with respect tothe automatic feed unit and tool holder, and the bottom of the body maybe brought into parallelism with the upper surface of the motor block.

The appropriate cutter 91 is then placed upon `the tool holder 93, thetool holder is slid upward into the bore of guide |54, and the completexture, including the supporting base 94, is secured to the engine blockby sliding the tool holder down over the cylindrical portion |05 of thepilot and simultaneously placing the body 94 over one -of the `stud.bolts on the motor block. The nut ||8 is then used to secure the body94 to the motor block, and while this is being done, the guide |54 andtool holder 93 are caused to take a position of alignment with respectto the axis of the valve stem guide between pilot 98. rPhe position ofthe cutter 91 is determined wholly by the valve stem pilot 98.

The nut |46 and bolt I 3| may then be threaded home to secure themovable bodies |24 and 95 in the position which they have taken, andassuming that it is proposed to cut a recess for a new valve seat ring,the feed screw should now be adjusted for a cut of the proper depth, asfollows.

All the lower edge |9| of the cutter blade |00 is permitted to rest onthe top of the motor block, and the feed screw |48 is turned upward ordownward in its supporting member until the fiat surface |52 is spacedfrom the end |5| of the gauge pins |58 by an amount which is equal tothe depth of the ring to be inserted in the recess. This can bedetermined by' holding the ring on one of the pins |50.

After the feed screw has been moved to this position, the clampingmember 2|3 is tightened by means of the bolt 2| 9, and the guide |54 isthus xedly secured to the tool holder 93, and, of course, to the cutter91, which is xedly mounted on the tool holder. The tool holder 93 maythen be actuated either by hand, with appropriate tools, such as aratchet wrench or by using the power drive unit and the motor previouslydescribed, by placing the socket 9| on the non-circular end 92 of toolholder 93.

The operation of the device under these conditions is as follows. Themotor I0 is driven at a relatively high speed due to the naturalcharacteristics of motors of this type, but the speed at the chuck isreduced by the speed reducing mechanism to a speed appropriate fordrills. The power drive unit further reduces the speed at the toolholder 93 to that appropriate for valve seat cutting operations, and themotor is thus adapted to drive the tool holder 93 at an appropriatespeed.

During this operation, the universal joint above the end of the toolholder 93 (Fig. l) permits the holding of the motor in any appropriateposition, and access may be had to valves located in practically anyposition on modern internal combustion engines. It is not necessary toeX- ert any pressure on the cutter by means of the handles of the motorfor the reason that the tool fixture l2 is fixedly secured to the motorblock, and the automatic feed screw unit 95 is adapted to automaticallymaintain a constant pressure on the cutter and feed the cutter at theproper rate with regard to the motor block.

As the tool holder 93 rotates, it carries with it the cutter 91 and theguide |54. The guide 54 carries with it the inner clutch ring |89 andthe position of the guide |54 is determined wholly by the pilot 98. Itshould be noted that the guide |54 is mounted for a limited universalmovement by virtue of the construction of the anti-friction bearing |6|,the balls |82 of which may .move upward or downward in the outer race:63. It should also be noted that there is a clearance between the endof the guide |54 and the feed screw |48, and a clearance between therespective clutch rings |13, |80. The respective clutch rings are, ofcourse, in engagement with the leather ring |55, but the shape of theseparts and the flexibility of the leather is such that a slight universalmovement is permitted at this point.

The cutter 91 ls thus guided entirely bythe pilot 98 so that it may outan accurately annular recess |03, the axis of which is identical withthe axis of the valve stem guide |91. The cutter reacts against toolholder 93, which reacts against guide |54, which in turn reacts againstthe anti-friction bearing |6| and against the valve tool body 94 in avertical direction.

The feed screw |48 is adapted to be driven also by the tool holder 93,for the reason that the outer clutch ring |13 carried by feed screw |58,is in frictional engagement with the leather ring |99, which is in turnengaged by the inner clutch ring |39. jected to resilient pressure bythe springs |59 and this pressure may be adjusted by moving the pressureadjustment member |8| upward or downward upon the threaded guide |54.

It is relatively immaterial where the slippage occurs with respect tothe leather ring |55, and the leather ring may slip with respect to theclutch ring |89 or clutch ring |13, or the pressure member |99. There isno possibility for the leather ring to bind with respect to the upperpressure ring |99 and carry the pressure adjustment member |8| alongwith it for the reason that the ball bearings 99 are interposed betweenthe pressure adjustment member |8| and the race |95.

The feed screw 48 is thus rotated at a rate which is predetermined bythe amount of slippage at the leather ring |55 and this slippage may beaccurately determined by the spring pressure on the leather ring. Theclutch pressure may be set at the factory when the device is inspected,and need only be taken up slightly from time to time as it appearsdesirable to rotate the feed screw at a higher rate. A low rate cfrotation of the feed screw is desirable, because this preventsoverworking the cutter.

The rotation of the feed screw |48, of course causes the feed screw toprogress downward in its supporting ring 95, thereby feeding downwardthe guide |54, tool holder 93 and cutter 91 until the pins |50 engage atsurface |52. No further downward motion of the feed screw beingpossible, the feed screw is positively held and full slippage must occurat the leather ring |55 so that no particular harm is done if the motoris operated for a few moments after the cutter has cut the predetermineddepth. The depth of cut is automatically stopped by the automatic feedscrew unit when the proper depth is reached. The other steps necessaryto finish the reconstruction of the valve set are described in my priorapplication above mentioned.

It will t-hus be observed that I have invented an improved valve seattool, by means of which valve seat work may be done With a minimumamount of manual labor. The applicants drill motor may be used for valveseat cutting operations, as well as drilling operations by means of theimproved power drive unit described herein, and the provision of theautomatic feed screw The leather ring |55 is subs unit enables thecutting of recesses for valve seat rings without the necessity formanually feeding the cutter. The proper adjustments having been made,the motor may be turned on and the recess is out automatically in anextremely short time.

The present valve seat tools are capable of cutting recesses orotherwise finishing valve seats more accurately than the devicesv of theprior art by virtue of tne fact that the cutter is perfectly alignedwith the best portion of the Valve stem guide, and this alignment isaccomplished within closer limits than any of thedevices of the priorart, as shown by test with thevalve seat gauges which are described inone ofmy prior applications.

While I havev illustrated a preferred embodiment of my invention, manymodifications may be made without departing from the spirit of theinvention, and I do not wish to be limited to the precise details ofconstruction set forth, but desire to avail myself of all changes withinthe scope of the appended claims.

Having thus described my invention, what I claim is new and'desire tosecure by Letters Patent of the United States, is:

1. In a valve seat working apparatus, the combination of a supportingfixture adapted to be secured to an 'internal engine block, saidsupporting xture having a threaded part for supportv of a feed screwunit, an automatic feed screw unit comprising a tubular body having athreaded surface for engagement with a supporting body, a bearingmounted in said tubular body, a guide carried by said bearing, andcooperating clutch members carried by said guide and said tubularmember, whereby said guide is adapted to drive said tubular member at areduced rate of speed.

2. In a valve seat working apparatus, the combination of a supportingfixture adapted to be secured to an internal engine block, saidsupporting fixture having a threaded part for support of a feed screwunit, an automatic feed screw unit comprising a tubular body having athreaded surface for engagement with a supporting body, a bearingmounted in said tubular body, a guide carried by said bearing,cooperating clutch members carried by said guide and said tubularmember, whereby said guide is adapted to drive said tubular member at areduced rate of speed, and means for adjusting the pressure on saidcooperating clutch members to determine the rate of drive of saidtubular member.

3. In an automatic feed screw unit, the combination of a supporting bodyhaving an externally threaded cylindrical surface for engagement with afixture, a sleeve rotatably mounted with respect to said body, saidsleeve and body having aligned bores, anti-friction bearings interposedbetween said sleeve and body, a pair of opposed frusto-conical memberscarried by said sleeve and body, said frusto-eonical members beingtapered in opposite directions forming a tapered groove, a taperedannular member mounted for engagement in said groove to slidably connectsaid sleeve and body for rotation together, and a tool holder slidablyadjustable with respect to saidsleeve and xedly secured to said sleevewhereby said body is rotated at a slower rate than said tool holder tofeed a tool carried by said tool holder.

4. In an automatic feed screw unit, the combination of a supporting bodyhaving an exter-V nallyl threaded cylindrical surface for engagementwith a xture, a sleeve rotatably mounted with respect to said body, saidsleeve and body having aligned bores, anti-friction bearings interposedbetween said'sleeve and body, a pair of opposed frusto-conical memberscarried by said sleeve and body forming a tapered groove, a taperedannular member mounted for engagement in said groove to slidably connectsaid sleeve and body for rotation together, and a tool holder slidablyadjustable with respect to said sleeve and xedly secured to said sleevewhereby said body is rotated at a slower rate than said tool holder tofeed a tool carried by said tool holder, and resilient means forengaging said V-shaped annular member and urging it into said groove.

5. In an automatic feed screw unit, the combination of a supporting bodyhaving an externally threaded cylindrical surface for engagement with axture, a sleeve rotatably mounted with respect to said body, said sleeveand body having aligned bores, anti-friction bearings interposedbetweensaid sleeve and body, a pair of opposed frusto-conical members carriedby said sleeve and body forming a tapered groove, a tapered annularmember mounted for engagement in said groove to slidably connect saidsleeve and body for rotation together, and a tool holder siidablyadjustable with respect to said sleeve and fixedly secured to saidsleeve whereby said body is rotated at Ya slower rate than said toolholder to*k feed a tool carried by said tool holder, and resilient meansfor engaging said V-shaped annular member and urging it into saidgroove,

a threaded member carried by said sleeve for adjusting the tension onsaid resilient means, and an anti-friction thrust bearing between saidthreaded member and said resilient means.

6` In an automatic feeding mechanism, the combination of a supportingmember with a threaded feed screw carried thereby, a tool holder, a toolcarried by said toolV holder and adapted to be fed toward the work bysaid feed screw, a tapered annular member carried by said tool holderand having an outer tapered surface, a second tapered annular membercarried by said feed screw and having an inner tapered surface taperingin a direction opposite to the said outer tapered surface, said innerand outer tapered surfaces being arranged in juxtaposition to bound anannular space which is of tapered shape when viewed in a section takenon a plane passing through the axis of the tool holder, and a taperedannular friction member floatingly mounted in said annular space andradapted to slidingly transmit power from the annular member carried bythe tool holder to the annular member carried by the feed screw to drivethe feed screw at a reduced speed.

7. In an automatic feeding mechanism, the combination of a supportingmember with a threaded feed screw carried thereby, a tool holder, a toolcarried by said tool holder and adapted to be fed toward the work bysaid feed screw, a tapered annular member carried by said tool holderand having an outer tapered surface, a second tapered annular membercarried by said feed screw and having an inner tapered surface taperingin a direction opposite to the said outer tapered surface, said innerand outer tapered surfaces being arranged in juxtaposition to bound anannular space which is of tapered shape when viewed in a section takenon a plane passing through the axis of the tool holder, and

a tapered annular friction member floatingly mounted in said annularspace and adapted to slidingly transmit power from the annular membercarried by the tool holder to the annular member carried by the feedscrew to drive the feed screw at a reduced speed, said friction membercomprising a leather ring of substantially V-shape.

8. In an automatic feeding mechanism, the combination of a supportingmember with a threaded feed screw carried thereby, a tool holder, a toolcarried by said tool holder and adapted to be fed toward the work bysaid feed screw, a tapered annular member carried by said tool holderand having an outer tapered surface, a second tapered annular membercarried by said feed screw and having an inner tapered surface, saidinner and outer tapered surfaces being arranged in juxtaposition tobound an annular space which is of tapered shape when viewed in asection taken on a plane passing through the axis of the tool holder, atapered annular friction member floatingly mounted in said annular spaceand adapted to slidingly transmit power from the annular member carriedby the tool holder to the annular member carried by the feed screw todrive the feed screw at a reduced speed, and resilient means for urgingsaid friction member into said annular space.

9. In an automatic feeding mechanism, the combination of a supportingmember with a threaded feed screw carried thereby, a tool holder, a toolcarried by said tool holder and adapted to be fed toward the work bysaid feed screw, a tapered annular member carried by said tool holderand having an outer tapered surface, a second tapered annular membercarried by said feed screw and having an inner tapered surface, saidinner and outer tapered surfaces being arranged in juxtaposition tobound an annular space which is of tapered shaped when viewed in asection taken on a plane passing through the axis of the tool holder, atapered annular friction member floatingly mounted in said annular spaceand adapted to slidingly transmit power from the annular member carriedby the tool holder to the annular member carried by the feed screw todrive the feed screw at a reduced speed, and resilient means for urgingsaid friction member into said annular space, said resilient meansreacting against a shoulder supported by said tool holder. l0. In anautomatic feeding mechanism, the combination of a supporting member witha threaded feed screw carried thereby, a tool holder, a tool carried bysaid tool holder and adapted to be fed toward the work by said feedscrew, a tapered annular member carried by said tool holder and havingan outer tapered surface, a second tapered annular member carried bysaid feed screw and having an inner tapered surface, said inner andouter tapered surfaces being arranged in juxtaposition to bound anannular space which is of tapered shape when viewed in a section takenon a plane passing through the axis of the tool holder, a taperedannular friction member fioatingly mounted in said annular space andadapted to slidingly transmit power from the annular member carried bythe tool holder to the annular member carried by the feed screw to drivethe feed screw at a reduced speed, resilient means for uging saidfriction member into said annular space, said resilient means reactingagainst a shoulder supported by said tool holder, and an anti-frictionbearing means interposed between said shoulder and said resilient means.

FRANS O. ALBERTSON.

